1. Technical Field
The present invention relates to a media transportation mechanism that transports CD's (Compact Discs), DVD's (Digital Versatile Discs), BD's (Blu-ray Discs), or other types of disc media, to a method of controlling a media transportation mechanism, and to a media processing device having the media transportation mechanism.
2. Related Art
Media processing devices such as CD/DVD publishers that write data and print labels on optical media to publish CDs and DVDs and other types of optical media are known from the literature. See, for example, Japanese Unexamined Patent Appl. Pub. JP-A-2009-26457. The media processing device described in JP-A-2009-26457 has a blank media stacker that holds a stack of blank unprocessed media to which data has not been burned, a processed media stacker in which processed media are stored in a stack, and a media transportation mechanism that holds and transports the media inside the publisher.
The media transportation mechanism has a transportation arm that can move up and down, and the transportation arm has a guide unit that is inserted into the center hole of the media, and a gripping mechanism that contacts the sides of the center hole and holds the media. The guide unit has a cylindrical base part, and a conical guide surface part that gradually decreases in diameter toward the bottom and is connected to the bottom end of the base part. The gripping mechanism has three fingers that contact the side of the center hole and grip the media. A round shoulder called a stacking ring for protecting the recording surface is formed around the center hole on the recording side of the CD, DVD, or other media.
Unprocessed media are stored in the blank media stacker with the recording surface facing down in the media processing device described in JP-A-2009-26457. As a result, the stacking ring of the top medium rests on the printing surface, which is the opposite side of the medium as the recording side, of the medium therebelow in the stacker, creating adhesion between the discs. When this happens and the transportation arm tries to pick the single disc (top-most medium) at the top of the media stacked in the blank media stacker, the disc immediately below (that is, the second disc from the top) may also be picked up with the top disc. Problems can then result where the discs are then released if the media are transported by the transportation arm with two discs stuck together. The transportation arm in the media processing device taught in JP-A-2009-26457 therefore has a kick lever that moves the disc on the bottom relative to the top disc, and separates the bottom disc from the top disc. The media transportation mechanism can therefore pick and transport only one disc from the top of the blank media stacker.
In addition to CD and DVD media, Blu-ray discs are also increasingly common. Whether or not a stacking ring is provided around the center hole on the recording surface side of Blu-ray discs, the height (thickness) of a Blu-ray disc is less than the height (thickness) of CD and DVD media with a stacking ring. As a result, when Blu-ray discs are stacked in the blank media stacker, the recording side of the top Blu-ray disc and the printing surface of the Blu-ray disc stacked therebelow can easily stick together. If the recording side and printing surface of two Blu-ray discs thus stick together, air cannot easily enter between the recording surface and printing surface, and the adhesion between two Blu-ray discs in the blank media stacker is therefore stronger than the adhesion between CD or DVD media.
Because the transportation arm of the media processing device described in JP-A-2009-26457 has a kick lever as described above, when CD or DVD media are stacked in the blank media stacker and two discs stick together inside the blank media stacker, the disc on the bottom can be separated and dropped from the top disc, and the single top disc can be picked and conveyed from the blank media stacker. However, when the media stacked in the blank media stacker are Blu-ray discs, the adhesion between the Blu-ray discs is greater than the adhesion between CD or DVD media. We discovered that when the media stacked in the blank media stacker are Blu-ray discs and two discs stick together in the blank media stacker, the top disc may be dropped from the transportation arm with the bottom disc as a result of this adhesion when the kick lever separates the bottom disc from the top disc.
More specifically, when the fingers 108 try to hold and lift the top disc 101 as shown in FIG. 12A, the next disc 102 therebelow sticks to the top disc 101, the top disc 101 and next disc 102 are lifted together by the transportation arm 105, and the kick lever 106 kicks the next disc 102 to separate the next disc 102 from the top disc 101, force F10 is applied to the next disc 102 in the direction the kick lever 106 kicks, and the next disc 102 moves in the direction kicked by the kick lever 106.
As a result, as shown in FIG. 12B, the side of the center hole 102a in the next disc 102 contacts the guide surface 107a of the guide unit 107, and force F20 is applied along the guide surface 107a to the next disc 102. This produces a moment M10 on the two discs 101 and 102 at the point where the top disc 101 contacts the fingers 108 as shown in FIG. 12C, the top disc 101 separates from the fingers 108, and the two discs 101 and 102 pivot.
As a result, the top disc 101 drops from the transportation arm 105 with the next disc 102 as shown in FIG. 12D.
In some cases the top disc 101 will separate from the fingers 108, catch on the kick lever 106, and not drop off, but when this happens a problem usually occurs where the top disc 101 is released.
A media transportation mechanism and a method of controlling a media transportation mechanism according to the present invention can reliably transport media one at a time even when the height of the stacking ring disposed to the media is low or a stacking ring is not formed on the media and adhesion between stacked media is strong.
Another object of at least one embodiment of the invention is to provide a media processing device that has this media transportation mechanism or has a media transportation mechanism that is controlled by the method of controlling this media transportation mechanism.